With a size that defies comprehension, behemoth whales grow to their mature size over untold centuries and can swallow entire ships whole.

Behemoth whales are unnaturally large. They are roughly 1,000 to 1,200 feet long and weigh about 400,000 tonnes, although some are rumored to be even greater in size. Some behemoth whales willingly transport sentients across the seas... and the planes.

Behemoth whales very rarely attack, and will usually only do so when provoked or when unwelcome creatures intrude upon their nesting grounds. Behemoth whales cannot make attacks of opportunity against creatures smaller than Gargantuan size.

Fantastic Size: Due to their enormous size, behemoth whales are difficult to harm. Damage from any area effect, and physical damage dealt by creatures of Huge size or smaller is halved (before applying damage reduction). Against smaller creatures, a behemoth whale incurs a cumulative -6 penalty to Spot checks for each size category below Gargantuan. Area effects with an effective radius smaller than 250 feet or that otherwise work in an area of comparable size only affect a behemoth whale partially, or not at all. From such sources, damage dealt is halved a second time, movement impairing effects are ignored completely, and any negative numerical effects are halved. Against all targeted spells, a behemoth whale has an effective spell resistance of 45 due to its massive size. Furthermore, a behemoth whale is immune to damage and drain to its physical ability scores (Strength, Dexterity and Constitution) , and doesn't automatically fail a Fortitude save on a roll of 1.

Behemoth whales may make only a single move action per round, and one standard action every other round. They may accelerate at a maximum of 10 feet per round up to their maximum swimming speed of 50 feet.

Hold Breath: A behemoth whale is gigantic beyond imagination, but its mammalean roots make it dependant on oxygen. A behemoth whale can hold its breath for a number of hours equal to its Constitution score (standardly 90 hours). The behemoth whale's need to breathe does not depend on the oxygen requirement of any creatures it may hold within its mouth.

Ingest Water (Ex): When a behemoth whale opens its gigantic maw, it draws massive amounts of water from the surrounding ocean in a 400 feet cone extending from its reach. Any creature in the water at a distance of less than 400 feet from the whale's reach must make a DC 80 Reflex save or be sucked towards the behemoth whale at a speed of 50 feet per round. For this purpose, any creature within the whale's reach counts as being at a distance of 0 feet. Creatures get a cumulative +10 bonus to this saving throw for every size category they have over Medium and for every 50 feet they are away from the whale respectively (to a maximum of +60). Creatures with ranks in the Swim skill may make a Swim check instead of a Fortitude save. A behemoth whale may ingest water for up to 1 minute at a time, after which it may gradually expel it over 1 minute. Using this ability is a free action.

Even ships can be drawn in by this intake of water. Ships of up to 300 feet long can be drawn towards the behemoth whale's maw, although ships of larger size may be forced to move at half speed.

Plane Shift (Su): A behemoth whale may plane shift, as the spell, at will. It requires 30 minutes in order to prepare the shift and traverse from one plane to the next. The whale may only plane shift while completely submerged and at least 1,000 feet deep. Any plane the whale desires to shift to must possess a sufficiently large body of salt water to sustain it. Although the whale's plane shift ability is susceptible to error same as the spell, it always ends up in a non-insular body of water. Spells that bar dimensional travel do not affect a behemoth whale's plane shift, although a sufficiently large antimagic area can prevent it from shifting.

When a behemoth whale plane shifts, it creates a magical current linking the waters of the seas on two different planes. As such, any aquatic creature can travel along across the planes provided it remains within the whale's reach. A creature that ventures out of the whale's reach during a plane shift is immediately ejected from the stream, unless it makes a DC 40 Fortitude save.

Swallow Whole (Ex): When one or more creatures or objects are drawn within the behemoth whale's reach due to its ingest water ability, it may swallow them as a standard action.

A behemoth whale can hold one Colossal+, 4 Colossal, 16 Gargantuan, 64 Huge, 256 Large or roughly 1,000 Medium or smaller creatures or objects. If it feels threatened, the behemoth whale may make an attack roll in order to deal crush damage equal to its bite to one or more swallowed creatures of Gargantuan or larger size every round. Smaller creatures within the whale's gizzard are not necessarily threatened, and may survive for lengthy periods of time.

Skills: A behemoth whale has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered.